JP3302482B2 - Internal abnormality detection device for gas insulation equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a gas circuit breaker and a GIS.
The present invention relates to a method and apparatus for detecting an internal abnormality of an SF ₆ gas-insulated device by measuring partial discharge.

[0002]

2. Description of the Related Art In gas-insulated equipment, the inside of a tank cannot be visually observed from the outside, so that internal abnormalities are detected by measuring partial discharge. FIG. 13 is a partially cutaway side view showing the configuration of a conventional internal abnormality detection device for gas-insulated equipment. The SF ₆ gas insulation device 1 has a configuration in which a circuit breaker 3 is housed in a tank 4, and both ends of the circuit breaker 3 are connected to an overhead wire 5 via a bushing 2. SF ₆ gas is sealed in the tank 4 and the electromagnetic wave sensor 6
Is provided in the manhole portion 4 </ b> A at the right end of the tank 4, and is connected to the signal processing unit 8 via the hermetic terminal 7. Further, the output signal of the signal processing unit 8 is sent to the display unit 9. A high-frequency current transformer 1 is connected to the ground wire 10 of the tank 4.
The output of the current transformer 11 is also sent to the display unit 9 via the signal processing unit 8. Further, an electromagnetic wave sensor 12 is installed via a pedestal 13 in proximity to the left outside of the tank 4, and an output signal of the electromagnetic wave sensor 12 is also sent to a display unit 9 via a signal processing unit 8.

[0003] FIG. 13 shows a diagram for measuring a partial discharge.
Two methods are shown at the same time. Electromagnetic wave sensor 6, 1
2. The current transformer 11 is a sensor for detecting a partial discharge and sending an electric signal to the signal processing unit 8. The electromagnetic wave sensors 6 and 12 are antennas that capture electromagnetic waves emitted by partial discharge. The electromagnetic wave sensor 6 captures an electromagnetic wave radiated from a partial discharge generated due to an abnormality inside the tank 4 inside the tank 4.
Captures electromagnetic waves radiated from the partial discharge generated by the internal abnormality of the tank 4 and leaks from the bushing 2 to the outside of the tank 4. Further, the current transformer 11 captures the partial discharge current since the partial discharge current generated due to the internal abnormality of the tank 4 flows through the ground line 10.

[0004] In any of the methods shown in FIG.
The signal processing unit 8 processes output signals from the electromagnetic wave sensors 6, 12 and the current transformer 11, and outputs a signal notifying that an abnormality has occurred inside the tank 4, The display 9 receives the output signal of the signal processing unit 8, and displays on the display or the cathode ray tube that the abnormality has occurred in the tank 4 on the display.

[0005]

However, the conventional apparatus as described above has a problem that it is not possible to detect an abnormality inside the tank because it is obstructed by partial discharge in the atmosphere generated outside the gas insulating apparatus. That is, in the outside of the tank, partial discharge in the air easily occurs at the overhead wire or the head of the bushing in rainy weather or the like. Electromagnetic waves and high-frequency currents caused by the partial discharge in the air enter the electromagnetic wave sensor and the current transformer as noise. When the noise level increases, the level of the partial discharge generated when an abnormality occurs inside the tank may be exceeded, and an abnormality inside the tank may not be detected.

FIG. 14 is a block diagram of the electromagnetic wave sensor 6 shown in FIG.
FIG. 3 is a frequency characteristic diagram of an electromagnetic wave captured by the apparatus. The horizontal axis indicates the frequency F, and the vertical axis indicates the level of the electromagnetic wave component. Characteristic 13 indicates that when an aerial partial discharge occurred on the overhead line 5, and characteristic 14 indicates that a partial discharge in the SF ₆ gas occurred when an abnormality occurred inside the tank 4. In this case, the characteristic 15 is a characteristic when the partial discharge in the overhead wire 5 and the partial discharge inside the tank 4 occur simultaneously. In each case, the output signal of the electromagnetic wave sensor 6 is output via a frequency analyzer.

[0007] In FIG. 14, it can be seen from the characteristic 13 that the partial discharge in the air has less frequency components of 0.5 GHz or more. On the other hand, from the characteristic 14, the partial discharge in SF ₆ gas was 0.8
It turns out that there are many frequency components above GHz. Each of the partial discharge detection devices in FIG. 13 does not include a frequency analyzer, so that when an electromagnetic wave having characteristics as shown in FIG. 14 is generated,
Only that peak value is detected. That is, in the case of the characteristic 14, the partial discharge inside the tank can be accurately measured, but in the case of the characteristics 13 and 15, the noise due to the partial discharge in the air disturbs and the partial discharge inside the tank is accurately measured. Can not do. That is, regardless of the presence or absence of the tank internal abnormality, only the noise level is detected, and the abnormality detection is erroneously determined.

In order to eliminate the erroneous determination of abnormality detection as described above, it is conceivable to cut an electromagnetic wave component of 0.7 GHz or less. As a method, it is conceivable to interpose a filter circuit that cuts off a frequency of 0.7 GHz or less or a band-pass filter circuit that passes only a specific frequency of 0.8 GHz or more on the output side of the electromagnetic wave sensor or the current transformer. . Although it is not impossible to remove noise by this filter circuit, it is very difficult to obtain the attenuation characteristics shown in the catalog even with a commercially available filter circuit. The reason is that, since high frequency is handled, if the installation location and wiring of the filter circuit are not carefully paid, the component of the frequency to be cut off bypasses the input / output wiring of the filter circuit. Also, if the grounding method of the filter circuit is not devised, the cutoff frequency component is transmitted to the output side of the filter circuit via the ground line.

An object of the present invention is to reliably remove components of a partial discharge in the air generated outside the tank and to detect only a partial discharge generated inside the tank.

[0010]

According to the present invention, there is provided, in accordance with the present invention, an apparatus for detecting an internal abnormality of a gas insulated apparatus in which electric equipment is stored in a tank filled with SF ₆ gas. Is formed from a conductor tube whose axial length is longer than the width or diameter of the lumen, and is attached to the tank wall with one end in the axial direction communicating with the inside of the tank.
A waveguide whose other end in the axial direction is gas-sealed, and an electromagnetic wave provided inside the waveguide and transmitted through the waveguide, detected and converted into an electric signal. An electromagnetic wave sensor that outputs a signal to the outside of the waveguide, and a signal processing unit that processes an electric signal output from the electromagnetic wave sensor and notifies that an abnormality has occurred inside the tank. A branch pipe is provided between the tank-side opening and the electromagnetic wave sensor so as to communicate with the waveguide, and the anti-waveguide side of the branch pipe is gas-sealed and a conductive end that closes the lumen inside the branch pipe. Preferably, a plate is provided. Further, in such a configuration, the end plate is slidably disposed in the axial direction of the branch tube lumen, one end is attached to the end plate, and the other end is drawn out of the branch tube. A drive unit may be provided which is gripped by the pipe and slides the end plate in the axial direction of the branch pipe.

According to another aspect of the present invention, there is provided an apparatus for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas. A conductor tube that is formed of a conductor tube whose axial length is longer than its width or diameter, is attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction is gas-sealed. A wave tube, an electromagnetic wave sensor provided inside the waveguide, detecting an electromagnetic wave propagating inside the waveguide, converting the detected electromagnetic wave into an electric signal, and outputting the electric signal to the outside of the waveguide; A signal processing unit for processing an electric signal output from the electromagnetic wave sensor and notifying that an abnormality has occurred inside the tank; and a lumen between the tank-side opening of the waveguide and the electromagnetic wave sensor. Is partially larger or wider It may be assumed that expansion pipe is formed by interposed. Further, in such a configuration, the expansion pipe may be a flexible pipe whose axis direction can be changed.

According to another aspect of the present invention, there is provided a device for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas. A conductor tube that is formed of a conductor tube whose axial length is longer than its width or diameter, is attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction is gas-sealed. A wave tube, an electromagnetic wave sensor provided inside the waveguide, detecting an electromagnetic wave propagating inside the waveguide, converting the detected electromagnetic wave into an electric signal, and outputting the electric signal to the outside of the waveguide; A signal processing unit for processing an electric signal output from the electromagnetic wave sensor and notifying that an abnormality has occurred inside the tank, and wherein the lumen of the waveguide is filled with a solid insulator. Good to do.

According to another aspect of the present invention, there is provided a device for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas. A conductor tube that is formed of a conductor tube whose axial length is longer than its width or diameter, is attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction is gas-sealed. A wave tube, an electromagnetic wave sensor provided inside the waveguide, detecting an electromagnetic wave propagating inside the waveguide, converting the detected electromagnetic wave into an electric signal, and outputting the electric signal to the outside of the waveguide; A signal processing unit for processing an electric signal output from the electromagnetic wave sensor and notifying that an abnormality has occurred inside the tank; and a wave guide between the tank side opening of the waveguide and the electromagnetic wave sensor. There is no wire mesh to block the lumen of the tube It may be the thing.

[0014]

According to the structure of the present invention, a waveguide communicating with the tank is provided, and the electromagnetic wave sensor is accommodated in the waveguide. Waveguides have different cutoff frequency components of electromagnetic waves traveling axially through the lumen depending on the width or diameter of the lumen. All electromagnetic waves below the cutoff frequency are attenuated and do not propagate in the axial direction. Therefore, if a waveguide having a cutoff frequency of at least 0.7 GHz is used, the component of the air partial discharge generated outside the tank is surely attenuated, and only the partial discharge in SF ₆ gas generated inside the tank is detected. be able to.

Further, in such a configuration, a branch pipe having a built-in termination plate is provided in the middle of the waveguide. The frequency component of the electromagnetic wave that can travel axially through the lumen of the waveguide is specified by the depth from the entrance of the branch pipe to the end plate. That is, the branch pipe serves as a band-pass filter for electromagnetic waves. Therefore, even if the cutoff frequency of the waveguide is not set to 0.7 GHz, the depth of the branch pipe is adjusted to 0.8 G by adjusting the depth of the branch pipe.
Only specific frequency components of not less than Hz can be passed, and only partial discharge in SF ₆ gas generated inside the tank can be detected.

Further, the terminal plate can be slid in the axial direction of the branch pipe by a driving unit from outside the tank via a driving rod. As a result, the depth of the branch pipe can be easily adjusted from the outside of the tank.
In the event that ambient noise having a specific frequency component of more than Hz enters, it is possible to detect only a partial discharge in SF ₆ gas while avoiding the specific frequency component.

Further, in such a configuration, an expansion pipe is interposed in the middle of the waveguide instead of the branch pipe. The axial length of the magnifying tube specifies the frequency component of the electromagnetic wave that can travel axially through the lumen of the waveguide. That is, the expansion tube also functions as a bandpass filter for electromagnetic waves. Therefore, only partial discharge in SF ₆ gas generated inside the tank can be detected in the same manner as in the above-described branch pipe.

In addition, by diverting the flexible pipe as the expansion pipe, even if the end of the waveguide is slightly displaced from the tank, the installation of the waveguide is facilitated. At the same time, earthquake resistance is improved. Also,
In such a configuration, the inner cavity of the waveguide is filled with a solid insulator instead of the expansion tube. Generally, the cutoff frequency of an electromagnetic wave largely depends on the dielectric constant. Assuming that the relative permittivity is ε, the lumen is filled with a gas having a larger ε than the gas (ε = 1). In order for a waveguide filled with a solid insulator to have the same value as the cut-off frequency of a gas-filled waveguide, the lumen width or diameter of the gas-filled waveguide divided by ε ^0.5 It may be of a width or diameter. Therefore, even if the cut-off frequency does not always match 0.7 GHz, the cut-off frequency can be reduced to 0.7 GHz by filling a solid insulator having an appropriate value of ε.
can be changed to z. Further, the waveguide can be made more compact by filling with a solid insulator having a large ε.

In such a configuration, a wire mesh is provided so as to close the inner cavity instead of filling the waveguide with a solid insulator. Since the wire mesh blocks the low frequency side of the electromagnetic wave, the component of 0.5 GHz or less is cut off by making the mesh of the wire mesh appropriate even if the cutoff frequency of the waveguide is not necessarily adjusted to 0.7 GHz. Only partial discharge in ₆ gases can be detected.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments and reference examples. FIG. 1 is a cross-sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas-insulated device according to a reference example of the present invention. The gas insulating device 1 has the same configuration as that of FIG. 13 in which the circuit breaker 3 is housed in the tank 4 and the bushing 2 is attached. The manhole part 4A of this tank 4
, A cylindrical waveguide 22 is attached, and SF ₆ gas is sealed. An electromagnetic wave sensor 23 is provided at the right end of the waveguide 22, and the signal processing unit 8 is
Connected to Further, the output signal of the signal processing unit 8 is sent to the display unit 9.

In FIG. 1, when a partial discharge in the SF ₆ gas occurs due to an abnormality inside the tank 4, electromagnetic waves radiated from the partial discharge enter the waveguide 22 from the tank 4 and pass through the waveguide 22. Propagation in the axial direction. Electromagnetic wave sensor 2
3 captures the transmitted electromagnetic wave, converts it into an electric signal, and sends it to the signal processing unit 8. The signal processing unit 8 processes the electric signal to output a signal notifying that an internal abnormality has occurred, and the display 9 displays on the display or a cathode ray tube that the abnormality has occurred inside the tank 4. Waveguide 22
Blocks an electromagnetic wave component below a specific frequency determined by its diameter.

FIG. 2 is a frequency characteristic diagram of an electromagnetic wave propagating in the waveguide 22 in the axial direction. The horizontal axis indicates the frequency F, and the vertical axis indicates the amount of attenuation of the electromagnetic wave level per unit length. The characteristic 25 is obtained when the waveguide 22 has a cylindrical shape and the bore diameter d is 250 mm, and Fc = 0.7 GH.
The attenuation becomes infinite at z. This Fc is called a cutoff frequency and depends on the diameter d.

FIG. 3 is a characteristic diagram showing the relationship between the bore diameter d of the waveguide and the cutoff frequency Fc, and the characteristic 26 indicates the characteristic of the fundamental mode electromagnetic wave in the cylinder. The cutoff frequency Fc decreases as the lumen diameter d increases. FIG. 4 is a frequency characteristic diagram of the electromagnetic wave captured by the electromagnetic wave sensor, in which the horizontal axis indicates the frequency and the vertical axis indicates the level of the electromagnetic wave component. Characteristic 2
7 and 28 both output an electromagnetic wave sensor output signal via a frequency analyzer when a partial discharge in the air occurs on the overhead wire outside the tank and a partial discharge in the SF ₆ gas also occurs inside the tank. It is a thing. Characteristic 27 is
The characteristic 28 is detected from the electromagnetic wave sensor 23 in the configuration shown in FIG. 1 and the characteristic 28 is detected from the electromagnetic wave sensor 6 in the conventional configuration shown in FIG. Characteristic 27 of FIG.
Is the same as the characteristic 15 in FIG. 14, and the frequency is 0.5
Aerial partial discharge noise was observed below GHz, and 0.8 GHz
This is a hindrance to the detection of the partial discharge in the SF ₆ gas described above. The characteristic 28 in FIG. 4 indicates that the waveguide 2 has a diameter d of 250 mm.
2 (cutoff frequency Fc is 0.7GHz)
And only partial discharge in SF ₆ gas is detected. In other words, the frequency component below 0.7 GHz is greatly attenuated by the interposition of the waveguide 22, so that the electromagnetic wave sensor 2
By sending the output signal of No. 3 to the signal processing unit 8, an abnormality inside the tank can be reliably detected.

In FIG. 3, the cut-off frequency F is applied to the waveguide.
In order to set c to 0.7 GHz, the lumen diameter d may be set to 250 mm. Therefore, in order to remove the noise and set the cutoff frequency to at least 0.7 GHz, the lumen diameter d of the waveguide may be set to 250 mm or less. In FIG. 1, the waveguide 22 may be a waveguide having an arbitrary shape such as a rectangular tube or an elliptic tube, and is not necessarily a cylinder. Here, it is omitted to show the characteristics of the conductive tube of another shape,
Cutoff frequency F determined by the shape and thickness of the lumen
c. However, in any shape of the conductive tube, the attenuation characteristic of the electromagnetic wave at the cutoff frequency Fc will not be as shown in FIG. 2 unless the axial length is secured to some extent. The axial length of the waveguide 22 should be at least the width of the lumen.
(In the case of a rectangular tube, the width of the long side) or the diameter (in the case of an elliptic tube, the long diameter) must be longer. This is the minimum condition for the conductor tube to function as the waveguide 22. In the conventional configuration of FIG. 13, the electromagnetic wave sensor 6 is housed in the manhole portion 4A at the right end of the tank 4,
The conductor tube of the manhole portion 4A does not function as a waveguide at all because its axial length is extremely shorter than its diameter.

FIG. 5 is a partially cutaway side view showing the configuration of an internal abnormality detecting device for a gas insulated device according to an embodiment of the present invention. In the middle of the waveguide 29, the tank 4 and the electromagnetic wave sensor 2
A branch pipe 30 is mounted between the end pipe 3 and a conductive end plate 31 therein. The end plate 31 is formed with an L-shaped groove 32 that goes around the outer peripheral wall, and is provided with a drive rod 33 whose other end is drawn out of the branch pipe 30 in an airtight manner. The drive rod 33 is connected to a drive unit 34 provided outside the branch pipe 30, and by rotating the drive unit 34, the end plate 31 can be slid in the axial direction of the branch pipe 30. Others are the same as the configuration of FIG.

In FIG. 5, an electromagnetic wave traveling in the axial direction of the waveguide 29 is limited to a specific frequency component by the branch tube 30. The specific frequency depends on the depth D from the entrance of the branch pipe 30 to the end plate 31. FIG. 6 shows the branch pipe 3
FIG. 9 is a characteristic diagram showing a relationship between a depth D of 0 and an attenuation of an electromagnetic wave propagating in the waveguide 29 in the axial direction (from Document 1).

Reference 1: Udagawa, "New Edition of Radio Engineering I Transmission Edition", published by Maruzen KK, 1980. The horizontal axis of FIG. 6 shows the depth D of the branch pipe, and the vertical axis shows the attenuation of electromagnetic waves. λ indicates the wavelength of the electromagnetic wave, and when the speed of light is C (= 3 × 10 ¹⁰ m / s), the frequency F is C / λ. Electromagnetic wave attenuation characteristics 3
5 is minimized when the depth D is λ / 4 or 3λ / 4. That is, when D = λ / 4,

[0028]

## EQU00001 ## Only the frequency component determined by F = C / .lambda. = C / 4D is propagated, and the other frequency components are greatly attenuated. This is the waveguide 2
9 is provided with a band-pass filter. Therefore, the cut-off frequency Fc of the waveguide 29 is not necessarily set to 0.7 GHz.
By adjusting the depth D of the branch pipe 30, only a specific frequency component of 0.8 GHz or more can be passed, and only partial discharge in SF ₆ gas generated inside the tank 4 is detected. be able to. If the diameter d of the waveguide 29 is large and the desired cutoff frequency Fc is too low, the role of the branch pipe 30 can be converted.

Referring back to FIG. 5, the depth D of the end plate 31 can be adjusted to a desired size by the drive unit 34. It is better that the end plate 31 completely closes the lumen of the branch pipe 30,
To make the end plate 31 slidable, a slight gap 31A is provided between the outer peripheral surface of the end plate 31 and the inner peripheral surface of the branch pipe 30.
Must be opened. As an L-shaped groove, A = B = λ /
By making the shape satisfy the relationship of No. 4, it is equivalent to the condition when there is no gap 31A equivalently.

FIG. 7 is a cross-sectional view of a main part showing a configuration of an internal abnormality detecting device for a gas insulated device according to another embodiment of the present invention. In the middle of the waveguide 36, between the tank 4 and the electromagnetic wave sensor 23, an enlarged tube 37 having a diameter larger than that of the waveguide 36 and having a length L in the axial direction is interposed. Others are the same as the configuration of FIG. In FIG. 7, the electromagnetic wave traveling in the axial direction in the waveguide 36 is limited to only a specific frequency component by the expanding tube 37. The specific frequency depends on the length L of the expansion tube.

FIG. 8 shows the length L of the expansion tube 37 and the length of the waveguide 36.
FIG. 7 is a characteristic diagram showing a relationship between the electromagnetic wave and the amount of attenuation of an electromagnetic wave propagating in the axial direction (from the aforementioned document 1). The horizontal axis in FIG. 8 indicates the length L of the expansion tube, and the vertical axis indicates the amount of attenuation of the electromagnetic wave. The attenuation characteristic 38 of the electromagnetic wave becomes minimum when the length L is λ / 2. That is, when L = λ / 2,

[0032]

## EQU00002 ## Only the frequency components determined by F = C / .lambda. = C / 2L propagate, and the other frequency components are greatly attenuated. This is the waveguide 3
6 is provided with a band-pass filter. Therefore, the cut-off frequency Fc of the waveguide 36 is necessarily set to 0.7 GHz.
By adjusting the length L of the expansion tube 37, only a specific frequency component of 0.8 GHz or more can be passed, and only partial discharge in SF ₆ gas generated inside the tank 4 is detected. be able to. When the diameter d of the waveguide 36 is large and the desired cutoff frequency Fc is too low, the function of the expanding tube 37 can be converted.

FIG. 9 is a cross-sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas-insulated device according to still another embodiment of the present invention. A flexible pipe 39 is interposed in the waveguide 40 as an enlarged pipe. Others are shown in FIG.
The configuration is the same as The flexible pipe 39 can be easily changed in the axial direction, and even if the terminal side (right side) of the waveguide 40 is slightly displaced from the tank side (left side), the flexible pipe 39 is absorbed. And the earthquake resistance is improved. By selecting a flexible pipe 39 whose inner diameter is larger than that of the waveguide 40,
It can have a function as an expansion tube.

FIG. 10 is a cross-sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas-insulated device according to still another embodiment of the present invention. A solid insulator 42 is provided in the lumen of the waveguide 41.
Fill. Others are the same as the configuration of FIG. FIG.
At 0, the lumen of the waveguide 41 is filled with a material having a higher relative dielectric constant ε than the gas. In order for the waveguide 41 filled with the solid insulator 42 to have the same value as the cut-off frequency Fc of the gas-filled waveguide, the diameter of the gas-filled waveguide divided by ε ^0.5 is used. What should I do? Therefore, even if the cutoff frequency Fc does not always match with 0.7 GHz, the cutoff frequency Fc can be changed to 0.7 GHz by filling the solid insulator 42 having an appropriate value of ε. Further, the waveguide 41 can be made more compact by filling the solid insulator 42 having a large ε.

FIG. 11 is a cross-sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas insulated apparatus according to a further different embodiment of the present invention. A wire mesh 44 is provided so as to close the inner cavity of the waveguide 43. FIG. 12 shows a diameter of 500 mm.
FIG. 7 is a frequency characteristic diagram of an electromagnetic wave propagating in the axial direction in the cylindrical waveguide of FIG. The horizontal axis indicates the frequency F, and the vertical axis indicates the amount of attenuation of the electromagnetic wave level per unit length. The characteristic 45 is for the case where the wire net 44 is not provided in FIG. 11, and the characteristic 46 is for the case where the wire net 44 is provided in FIG. Characteristic 4
Although the cut-off frequency Fc of No. 5 is 0.35 GHz, which is too low to remove noise, the low-frequency side can be cut off as shown by the characteristic 46 by installing the wire netting 44. Since only the frequency component of the hatched area 47 is detected, the waveguide 43
Even if the cutoff frequency Fc is not appropriate, the partial discharge in the SF ₆ gas can be detected by installing the wire mesh 47.

In FIG. 12, the characteristic 46 changes depending on the mesh of the wire mesh, and the smaller the mesh, the higher the frequency shifts. Therefore, by selecting the type of wire mesh, it is possible to detect a wire having a desired frequency component.

[0037]

According to the present invention, as described above, the waveguide communicating with the tank is provided, and the electromagnetic wave sensor is accommodated in the waveguide. Thus, the abnormality in the tank can be reliably detected without using a filter circuit that is difficult to use, and the detection sensitivity is improved. In such a configuration, a branch pipe having a built-in termination plate is provided in the middle of the waveguide. Thus, only a specific frequency component of the electromagnetic wave can be detected, and even if the width or diameter of the waveguide is not appropriate, an abnormality inside the tank can be reliably detected.

In this configuration, the end plate in the branch pipe is made slidable by the driving unit from outside the tank via the driving rod. This makes it possible to externally adjust the depth of the branch pipe. Even if ambient noise of a specific frequency component enters, the SF is avoided by avoiding the specific frequency component.
₆ Only partial discharge in gas can be reliably detected,
The detection sensitivity is improved.

In such a configuration, an expansion pipe is interposed in the middle of the waveguide instead of the branch pipe. Again,
Only a specific frequency component of the electromagnetic wave can be detected, and even if the width or diameter of the waveguide is not appropriate, an abnormality inside the tank can be reliably detected. In such a configuration, a flexible pipe is used as the expansion pipe.
This facilitates the installation work of the device and improves the earthquake resistance. In such a configuration, the solid insulator is filled in the lumen of the waveguide instead of the expansion tube. Thereby, even if the width or diameter of the waveguide is not appropriate, an abnormality inside the tank can be reliably detected and the waveguide can be made compact.

In such a configuration, instead of filling the waveguide with a solid insulator, a wire mesh is provided so as to close the inner cavity. Thus, even if the cutoff frequency of the waveguide is too low for noise removal and is not appropriate, the wire mesh removes the noise component, so that an abnormality in the tank can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing a configuration of an internal abnormality detection device for a gas-insulated device according to a reference example of the present invention.

FIG. 2 is a frequency characteristic diagram of an electromagnetic wave propagating in a waveguide.

FIG. 3 is a characteristic diagram showing a relationship between a bore diameter d of the waveguide and a cutoff frequency Fc.

FIG. 4 is a frequency characteristic diagram of an electromagnetic wave captured by the electromagnetic wave sensor.

FIG. 5 is a partially cutaway side view showing a configuration of an internal abnormality detection device for a gas-insulated device according to an embodiment of the present invention.

FIG. 6 is a characteristic diagram showing the relationship between the depth D of the branch pipe and the attenuation of electromagnetic waves propagating through the waveguide.

FIG. 7 is a cross-sectional view of a main part showing a configuration of an internal abnormality detection device for a gas-insulated device according to another embodiment of the present invention.

FIG. 8 is a characteristic diagram showing the relationship between the length L of the magnifying tube and the attenuation of electromagnetic waves propagating through the waveguide.

FIG. 9 is a cross-sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas-insulated device according to still another embodiment of the present invention.

FIG. 10 is a cross-sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas-insulated device according to still another embodiment of the present invention.

FIG. 11 is a sectional view of a main part showing a configuration of a device for detecting an internal abnormality of a gas-insulated device according to still another embodiment of the present invention.

FIG. 12 is a frequency characteristic diagram of an electromagnetic wave propagating in a cylindrical waveguide having a diameter of 500 mm.

FIG. 13 is a partially cutaway side view showing the configuration of a conventional internal abnormality detection device for a gas-insulated device.

14 is a frequency characteristic diagram of an electromagnetic wave captured by the electromagnetic wave sensor 6 in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas insulation apparatus 2 Bushing 3 Circuit breaker 4 Tank 4A Manhole part 8 Signal processing part 9 Display part 22, 29, 36, 40, 41, 43 Waveguide 23 Electromagnetic wave sensor 30 Branch pipe 31 Termination plate 31A Gap 32 L-shaped groove 33 Drive Rod 34 Drive 37 Enlarged Tube 39 Flexible Pipe 42 Solid Insulator 44 Wire Mesh

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoyuki Hosoi 1-1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd. (72) Inventor Kenji Matsuura 5-14- Hiyoshidai, Takatsuki-shi, Osaka 24 (72) Inventor Zenichiro Kawasaki 2-1023, Nishijima-cho, Moriguchi-shi, Osaka 2-1023 (56) References JP-A-3-57977 (JP, A) JP-A-1-278222 (JP, A) 2-223871 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 31/12 H02B 13/065 H02H 5/00

Claims (6)

(57) [Claims] 1. A device for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas, wherein the conductor tube has an axial length longer than a width or a diameter of a lumen. A waveguide formed and attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction gas-sealed, and provided inside the waveguide. An electromagnetic wave sensor that detects an electromagnetic wave that has propagated inside the waveguide and converts it into an electric signal, and outputs the electric signal to the outside of the waveguide, processes the electric signal output from the electromagnetic wave sensor, A signal processing unit for notifying that an abnormality has occurred inside, and a branch pipe is provided between the tank-side opening of the waveguide and the electromagnetic wave sensor in communication with the waveguide, and a branch pipe is provided. The anti-waveguide side is gas-sealed and the inside of the branch tube Internal abnormality detecting device for a gas insulated apparatus electrically conductive end plate closing the lumen is provided. 2. The driving rod according to claim 1, wherein the end plate is slidably disposed in the axial direction of the lumen of the branch tube, and one end is attached to the end plate and the other end is drawn out of the branch tube. And a drive unit for gripping the drive rod outside the branch pipe and sliding the end plate in the axial direction of the branch pipe. 3. An apparatus for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas, wherein the conductor tube has an axial length longer than a width or a diameter of a bore. A waveguide formed and attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction gas-sealed, and provided inside the waveguide. An electromagnetic wave sensor that detects an electromagnetic wave that has propagated inside the waveguide and converts it into an electric signal, and outputs the electric signal to the outside of the waveguide, processes the electric signal output from the electromagnetic wave sensor, A signal processing unit for notifying that an abnormality has occurred inside, and an expanding tube having a partially increased width or diameter of the lumen interposed between the tank-side opening of the waveguide and the electromagnetic wave sensor. Gas insulation machine characterized by being mounted Internal abnormality detection device. 4. The apparatus according to claim 3, wherein the expansion pipe is a flexible pipe whose axis direction can be changed. 5. An apparatus for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas, wherein the conductor tube has an axial length longer than a width or a diameter of a lumen. A waveguide formed and attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction gas-sealed, and provided inside the waveguide. An electromagnetic wave sensor that detects an electromagnetic wave that has propagated inside the waveguide and converts it into an electric signal, and outputs the electric signal to the outside of the waveguide, processes the electric signal output from the electromagnetic wave sensor, An internal abnormality detection device for a gas insulated device, comprising: a signal processing unit for notifying that an abnormality has occurred therein; and wherein the lumen of the waveguide is filled with a solid insulator. 6. An apparatus for detecting an internal abnormality of a gas insulated device in which an electric device is housed in a tank filled with SF ₆ gas, wherein the conductor tube has an axial length longer than a width or a diameter of a lumen. A waveguide formed and attached to the tank wall with one end in the axial direction communicating with the inside of the tank, and the other end in the axial direction gas-sealed, and provided inside the waveguide. An electromagnetic wave sensor that detects an electromagnetic wave that has propagated inside the waveguide and converts it into an electric signal, and outputs the electric signal to the outside of the waveguide, processes the electric signal output from the electromagnetic wave sensor, A signal processing unit for notifying that an abnormality has occurred inside, and that a wire mesh for closing the lumen of the waveguide is provided between the tank-side opening of the waveguide and the electromagnetic wave sensor. Characteristic internal abnormality detection device for gas insulation equipment.